Steering Mechanism

ABSTRACT

A steering lever mechanism for a mower vehicle includes a lever assembly and a base which is fixed to the mower vehicle for mounting the lever assembly to the mower. The lever assembly includes a pivot assembly and a lever portion. The lever portion is pivotably mounted to the pivot assembly for rotation about a longitudinal axis between an inboard position and an outboard position. The pivot assembly is also pivotably mounted to the base for rotation of the pivot bracket portion and the lever portion about a transverse axis between a rear position, an intermediate neutral position and a forward position. A rotation-measuring device is associated with the base and the pivot assembly for measuring the forward and rear rotation of the lever assembly.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of, and claims priority to, pendingU.S. Nonprovisional application Ser. No. 14/621,745 filed Feb. 13, 2015,now (the “'745 application”). The '745 application is a continuation ofU.S. Nonprovisional application Ser. No. 13/584,282 filed Aug. 13, 2012(the “'282 Application”). The '282 application is a continuation-in-partof U.S. application Ser. No. 12/586,411 filed Sep. 22, 2009, now U.S.Pat. No. 8,240,420 (the “'411 application”). The '411 application claimsthe benefit of U.S. Provisional Application No. 61/197,199 filed Oct.23, 2008. The entireties of the aforementioned applications are eachincorporated herein by reference.

FIELD

The present invention relates to a steering mechanism for a riding lawnmower.

BACKGROUND

Zero turn electric lawn mowers have been known in the art for severalyears. An example combined steering and brake control lever mechanism istaught by U.S. Pat. No. 6,729,115 issued to Bartel. The applicant'sincorporate U.S. Pat. No. 6,729,115 herein as if repeated verbatimhereinafter. U.S. Pat. No. 6,729,115 teaches a mechanism which includesleft and right steering levers. In the arrangement taught in U.S. Pat.No. 6,729,115 each of the steering levers independently controlhydraulic valves which in turn control the flow of hydraulic fluid toone of either the left or right hydraulic drive wheel motors. Thus, inthe steering control system taught in U.S. Pat. No. 6,729,115, if theoperator pushes the right steering lever forward of the neutralposition, the right drive wheel will rotate in a forward direction andif the operator pulls the right steering lever back from the neutralposition, the right drive wheel will rotate in a reverse direction. Thesame is true for the left steering lever. Moreover, in the arrangementtaught in U.S. Pat. No. 6,729,115, each steering lever may be pushedoutboard when it is in the neutral position and if the operator pushes asteering lever outboard from the neutral position, a linkage is actuatedto engage a parking brake associated with the wheel on the same side ofthe mower. The driving feel of the hydraulic based arrangement describedin U.S. Pat. No. 6,729,115 has been well received by operators. Thehydraulic valves of the arrangement described in U.S. Pat. No. 6,729,115provide feedback resistance in response to steering lever movements.Also, in the arrangement taught in U.S. Pat. No. 6,729,115 the outwardmovement of a steering handle from the neutral position to engage aparking brake moves linkage members in a parking brake linkage which inturn provides mechanical resistance to the outward movement of thehandle. If an electric steering interface is selected for accomplishingthe general functions of the arrangement taught by U.S. Pat. No.6,729,115, then the problem of providing feedback through the steeringhandles to the operator arises. What is needed is an electric zero turnradius (ZTR) steering and brake interface which provides substantiallythe same feel as the arrangement taught in U.S. Pat. No. 6,729,115.

BRIEF DESCRIPTION OF THE INVENTION

The present invention answers this need by providing steering levermechanism which includes a lever assembly and a base including at leastone bracket fixed to the frame of the mower vehicle for mounting thelever assembly to a mower vehicle. The lever assembly includes a pivotassembly and a lever portion. The pivot assembly is pivotably mounted tothe base for rotation of the pivot assembly and the lever portion abouta transverse axis between a rear position, an intermediate neutralposition and a forward position. A position-measuring device isassociated with the base and the pivot assembly for measuring theforward and rear rotation of the lever assembly. A mechanical resistancedevice connects between pivot assembly and the frame of the mowervehicle for resisting rotation of the pivot assembly and the leverassembly between the forward position and the rear position. The leverportion is also pivotably mounted to the pivot assembly for rotationabout a longitudinal axis between an inboard position and an outboardposition. A sensor for activating a parking brake is also associatedwith the base for sensing the lever portion when it is in the outboardposition. A cam member is fixed to the lever portion and has first andsecond recesses. A cam follower is pivotably mounted to the pivotassembly and is spring biased for engaging one of the first or secondrecesses of the cam member. The cam follower and the cam member arearranged such that the cam follower is urged into the first recess whenthe lever portion is in the inboard position and such that the camfollower is urged into the second recess when the lever portion is inthe outboard position. At least one of the brackets of the base includesa slot which is located to receive the lever portion when the leverportion is in the neutral position (with respect to forward and backwardrotation) as the lever portion rotates outboard. A stop member fixed tothe base prevents the lever portion from rotating past the neutraloutboard position. A sensor associated with the stop member produces asignal when the lever portion is in the neutral outboard position.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a first perspective view of the steering lever mechanism ofthe present invention.

FIG. 2 is a second perspective view of the steering lever mechanism ofthe present invention.

FIG. 3 is a third perspective view of the steering lever mechanism ofthe present invention.

FIG. 4 is a sectional view of the steering lever mechanism of thepresent invention taken from plane A-A of FIG. 1 showing the leverassembly in the inboard position.

FIG. 5 is a sectional view of the steering lever mechanism of thepresent invention taken from plane A-A of FIG. 1 showing the leverassembly in the outboard position.

FIG. 6 is a first perspective view of a second embodiment of thesteering lever mechanism having a mechanical linkage for engaging aparking brake showing the steering lever in the neutral inboardposition.

FIG. 6A is a second perspective view of a second embodiment of thesteering lever mechanism showing the steering lever in the first back oraft position.

FIG. 6B is a third perspective view of a second embodiment of thesteering lever mechanism showing the steering lever in the secondforward position.

FIG. 7 is a fourth perspective view of the second embodiment of thesteering lever mechanism showing the steering lever in the secondoutboard parking brake setting position.

DETAILED DESCRIPTION

Referring to the drawings, FIG. 1 provides a perspective view of asteering lever mechanism 10 which is mounted to a mower vehicle frame 2.Steering lever mechanism 10 generally includes a base 20 and a leverassembly 100. Base 20 further includes an outboard bracket 22 and aninboard bracket 24 (shown in FIG. 4) which are both fixed to a frame 2of the mower vehicle.

As can be best seen in FIGS. 2-5, lever assembly 100 includes a leverportion 110 and a pivot assembly 150. Lever portion 110 includes a lowerlever member 112 and a handle 114 which is fixed to the upper end oflower lever member 112. Handle 114 preferably includes padding 114A foroperator comfort.

Pivot assembly 150 includes a pivot shaft 152 and a pivot bracketassembly 160. As is best shown in FIGS. 4 and 5, pivot shaft 152 isrotatably mounted to brackets 22 and 24 of base 20 for rotation aboutaxis A which is generally a transverse axis parallel to the axis labeledINBD in the various figures. Pivot shaft 152 carries a pivot bracketassembly 160. As will be described in greater detail below, pivotbracket assembly 160 carries lever assembly 100.

Lever assembly 100 is pivotably mounted to pivot bracket assembly 160 sothat when permitted by a transverse slot 22A located near the upper endof outboard bracket 22, lever assembly 100 can rotate about axis B shownin FIG. 2 between an inboard position shown in FIG. 4 and an outboardposition shown in FIG. 5. A cam follower arrangement is interposedbetween lever assembly 100 and pivot bracket assembly 160 so that leverassembly 100 is urged into one of the two above described positions aswill be described in greater detail below.

As noted above, lower lever member 112 of lever assembly 100 ispivotably mounted to the upper end of pivot bracket assembly 160 forrotation about axis B shown in FIG. 2. As can best be seen in FIG. 4, acam plate 116 is fixed to the lower end of lower lever member 112. Camplate 116 includes a first recess 116A and a second recess 116B whichare both adapted for receiving a cam roller 202. Cam roller 202 isrotatably mounted to a cam follower 200. Cam follower 200 is, in turn,pivotably mounted to pivot bracket assembly 160 for rotation about axisC shown in FIGS. 2 and 3. At its lower end below axis C and oppositefrom cam roller 202, cam follower 200 is spring biased by a compressionspring 170 which urges cam roller 202 into one of first or second recess116A or 116B of cam plate 116. Cam plate 116 is configured and locatedso that cam roller 202 tends to retain its position in either first orsecond recess 116A or 116B and does not move to the other recess unlessan operator applies a force to lever assembly 100. Accordingly, leverassembly 100 tends to remain in the inboard position shown in FIG. 4 andwhen received by slot 22A will remain in the outboard position shown inFIG. 5 unless acted upon. An outboard lever position sensor 280 (shownin FIG. 4) mounted to outboard bracket 22 is adapted to detect leverassembly 100 when it is in the outboard position as shown in FIG. 5.Outboard lever position sensor 280 is preferably in communication with aparking brake system which, upon receiving an outboard position signal,engages at least one parking brake.

Lever assembly 100 is fixed to pivot bracket assembly 160 whenconsidered from the perspective of rotation about a transverse axis.However pivot bracket assembly 160 is mounted to brackets 22 and 24 byshaft 152 for rotation about a transverse axis A shown in FIGS. 2 and 3.Shaft 152 interfaces with a rotation measurement device 300 mounted onthe outboard side of outboard bracket 22. Position measurement device300 may be potentiometer which is well known to those skilled in the artor any other suitable device capable of measuring displacement orrotation. Position measurement device 300 provides signals to a drivecontrol system (not shown) which in turn determines whether the drivewheel controlled by lever assembly 100 rotates in a reverse direction, aforward direction or is stationary as indicated by a neutral leverassembly position such that the forward position indicates forwardrotation at a maximum forward speed and such that the rear positionindicates reverse rotation at a maximum reverse speed and so on forlesser speeds of rotation as indicated by intermediate positions of thelever assembly 100 between the neutral position and either the forwardor rear positions.

The rotation of lever assembly 100 and the rotation of pivot bracketassembly 160 about axis A is resisted by a dampener unit 400 whichconnects between the extreme lower end of pivot bracket assembly 160 andvehicle frame 2. In this example dampener unit 400 is a linear dampenerwhich is adapted to resist the rotation of pivot bracket assembly 160(and thus lever assembly 100) either in a forward or rear directionabout axis A. In this example, dampener unit 400 preferably includes acompression spring 402 which is positioned within dampener unit 400 suchthat spring 402 biases lever assembly 100 away from the rear positionand toward the neutral position. With this arrangement, the operatormust apply constant pressure to cause the mower to move in reverse, yet,the operator merely moves lever assembly 100 to a forward position andholds lever assembly 100 in the selected forward position withoutapplying constant pressure in order to cause the mower to move forward.In this example, dampener member 400 is pivotably connected to frame 2at its distal end and pivotably connected at its proximate end to acylindrical lug 170 which is fixed to the lower end of pivot bracketassembly 160. Cylindrical lug 170 is spaced away form the axis ofrotation A of pivot bracket assembly 160 so that rotation of pivotbracket assembly 160 about axis A causes displacement of the proximateend of dampener member 400 relative to the fixed distal end of dampenermember 400.

FIGS. 6 and 7 illustrate a second embodiment steering mechanism 1010which employs a mechanical parking brake linkage 1170. Steeringmechanism 1010 includes a pivot bracket assembly 1160 which is rotatablymounted to the frame of a riding lawnmower (not shown) for rotationabout axis A. Thus, pivot bracket assembly 1160 rotates about axis Abetween a first position as shown in FIG. 6A, through a neutral positionshown in FIG. 6 to a second position shown in FIG. 6B. A positionmeasurement device 1130 which in this example is a potentiometer thatmeasures rotation of bracket assembly 1160 about axis A with respect tothe vehicle frame. A damper unit 1400 generally similar to damper unit400 described above is also connected between the frame of the mowervehicle 2 and pivot bracket assembly 1160. Damper unit 1400 performsgenerally the same function for steering mechanism 1010 as does damperunit 400 for steering mechanism 10 described above. A lever assembly1110 is pivotably mounted to pivot bracket assembly 1160 for rotationwith respect to pivot bracket assembly 1160 about axis B which, in thisexample, is generally normal to axis A but fixed with respect to pivotbracket assembly 1160. Lever assembly 1110 pivots between a firstposition shown in FIG. 6 and a second position shown in FIG. 7 which inthis example is a first inboard position and a second outboard positionrespectively. The skilled reader should understand that an identicalsymmetrical steering mechanism 1010 is also present on the opposite sideof the mower vehicle which is only indicated a frame 2 in FIGS. 6-7.

FIG. 6 shows steering mechanism 1010 with lever 1110 in the first,inboard operating position. FIGS. 6-7 illustrate a mechanical parkingbrake mechanism 1170 that extends between the lower end of lever 1110and a parking brake 1190 which is associated with one of the wheels ofthe mower. As can be seen in FIG. 6, when lever 1110 is in the first,inboard position, parking brake mechanism 1170 is generally in an aftposition appropriate for disengaging a parking brake 1190. When lever1110 is pivoted to the second, outboard parking brake setting positionshown in FIG. 7, lever 1172 is pivoted inboard. When lever 1172 pivotsinboard, a brake pivot plate 1174 rotates clockwise (when viewed fromabove) about an axis C which is fixed relative to frame 2. The clockwiserotation of pivot plate 1174 causes connecting rod 1178 to be pulledforward which causes a brake bracket 1180 to be rotated forward to setparking brake 1190. The configuration and operation of a mechanicalparking brake mechanism which is similar to parking brake mechanism 1170is also described in U.S. Pat. No. 6,434,917 which is incorporatedherein by reference.

It is to be understood that while certain forms of this invention havebeen illustrated and described, it is not limited thereto, except in sofar as such limitations are included in the following claims andallowable equivalents thereof

What is claimed is:
 1. An electric zero turn radius (“ZTR”) vehiclehaving a vehicle frame and right and left drive wheels that are eachpowered by a respective left or right drive wheel motor, a steeringmechanism, and a parking brake mechanism, the steering mechanismcomprising: a pair of control lever assemblies including a right controllever assembly for controlling the right drive wheel motor and a leftcontrol lever assembly for controlling the left drive wheel motor, eachcontrol lever assembly including, (1) a pivot bracket assembly which ispivotably mounted to the frame of the electric ZTR vehicle for rotationabout a first axis between a first position, through a neutral positionand a second position, wherein the pivot bracket assembly has anoutboard side and an opposite inboard side, and (2) a positionmeasurement device operably associated with the vehicle frame and theinboard side of the pivot bracket assembly by a shaft extendingtransverse between the vehicle frame and the pivot bracket assembly, theposition measurement device is operable to measure the rotation ordisplacement of the pivot bracket assembly with respect to the vehicleframe in relation to the first position and the second position, theposition measurement device being able to provide signals forcontrolling the direction of rotation and speed of rotation of said oneof the drive wheel motors.
 2. The electric ZTR vehicle of claim 1,wherein each control lever assembly further comprises a dampener unitconnecting between the pivot bracket assembly and the vehicle framesuitable for resisting the movement of the pivot bracket assembly. 3.The electric ZTR vehicle of claim 2, wherein the dampener unit furtherincludes a spring for biasing the pivot bracket assembly toward theneutral position.
 4. The electric ZTR vehicle of claim 1, wherein eachcontrol lever assembly further comprises a lever assembly pivotablymounted to the pivot bracket assembly for rotation with respect to thepivot bracket assembly about a second axis between a first inboardposition and a second outboard position.
 5. The electric ZTR vehicle ofclaim 4, wherein the lever assembly is interconnected with the parkingbrake mechanism such that moving the lever assembly to the secondoutboard position sets the parking brake.
 6. The electric ZTR vehicle ofclaim 1, wherein the steering lever mechanism further comprises at leastone sensor associated with at least one of the control lever assembliesfor detecting when the at least one control lever assembly is in thesecond outboard position.
 7. The electric ZTR vehicle of claim 1 furthercomprising a drive control system capable to determine the direction ofrotation and the speed of rotation of said one of the drive wheel motorsfrom the position measurement device provided signals.
 8. An electriczero turn radius (“ZTR”) vehicle having a vehicle frame and right andleft drive wheels that are each powered by a respective left or rightdrive wheel motor, a steering mechanism, and a parking brake mechanism,the steering mechanism comprising: a pair of control lever assembliesincluding a right control lever assembly for controlling the right drivewheel motor and a left control lever assembly for controlling the leftdrive wheel motor, each control lever assembly including, (1) a pivotbracket assembly which is pivotably mounted to the frame of the electricZTR vehicle for rotation about a first axis between a first position,through a neutral position and a second position, wherein the pivotbracket assembly has an outboard side and an opposite inboard side, (2)a lever portion which is pivotally mounted to the pivot bracket assemblyfor rotation with respect to the pivot bracket assembly about a secondaxis between a first inboard position and a second outboard position,and (3) a position measurement device operably associated with thevehicle frame by a shaft extending transverse between the vehicle frameand the pivot bracket assembly, the position measurement device isoperable to measure the rotation or displacement of the pivot bracketassembly with respect to the vehicle frame in relation to the firstposition and the second position, the position measurement device beingable to provide signals for controlling the direction of rotation andspeed of rotation of said one of the drive wheel motors.
 9. The electricZTR vehicle of claim 8, wherein the first axis is orthogonal to thesecond axis.
 10. The electric ZTR vehicle of claim 9, wherein the secondaxis is vertically offset from the first axis.
 11. The electric ZTRvehicle of claim 8, wherein the pivot bracket assembly is in the neutralposition when the lever portion is in the first inboard position. 12.The electric ZTR vehicle of claim 8, wherein the position measurementdevice is operably associated with the vehicle frame and the inboardside of the pivot bracket assembly.
 13. The electric ZTR vehicle ofclaim 8, wherein the position measurement device is operably associatedwith the vehicle frame and the outboard side of the pivot bracketassembly.
 14. The electric ZTR vehicle of claim 8, wherein the leverportion further comprises: a lower member having an upper end and alower end, the lower member pivotally mounted to the pivot bracketassembly between the upper end and the lower end; and a brake linkageoperatively coupled to the lower end of the lower member for engagementof a parking brake and disengagement of the parking brake, wherein theparking brake is engaged when the lever portion is in the secondoutboard position and the parking brake is disengaged when the leverportion is in the first inboard position.
 15. The electric ZTR vehicleof claim 14 further comprising: the pivotal mounting between the lowermember and the pivot bracket assembly being spaced a first distanceabove the first axis; and the lower member extending from the pivotalmounting to the lower end a second distance, wherein the second distanceis greater than the first distance.
 16. The electric ZTR vehicle ofclaim 14, wherein the brake linkage further comprises: a lever coupledproximate the lower end of the lower member, the lever extending to andcoupled with a brake pivot plate; the brake pivot plate pivotallymounted to the frame; a connecting rod coupled to the brake pivot plate,the connecting rod extending to and coupled with a brake bracket, thebrake bracket configured to set the parking brake upon actuation of thebrake linkage.
 17. The electric ZTR vehicle of claim 14 furthercomprising a handle is fixed to the upper end of the lower member.